1. Field of the Invention
This invention concerns a process for manufacturing a polyetheresteramide and, more specifically, it relates to a process for producing a colorless polyetheresteramide with a high degree of polymerization using one or more polyamide-forming compound selected from the group consisting of aminocarboxylic acids or lactams, a dicarboxylic acid and a polyoxyalkylene glycol as starting materials.
2. Description of the Prior Art
Polyetheresteramides contain polyamide repeating units, polyether repeating units and ester bonds in the main polymer chain, and they have attracted attention in recent years as novel materials in the field of elastomers since they have excellent impact shock property and rubber-like elasticity comparable with those of polyester elastomer or polyurethane elastomer.
Since the polyetheresteramides are particularly excellent in view of their light weight, low temperature performance, chemical resistance, oil resistance, sound proofness and molding property, much demand is expected for them in the fields such as hoses, tubes and wiper rubbers for automobiles and shoe soles for sport shoes, as well as those fields where severe quality is required in sanitary point of view such as food stuffs and medical equipments.
However, the polyetheresteramides involve a problem that they are colored due to a certain kind of decomposing reaction upon polymerization and, although several improvements have been proposed so far, none of them was satisfactory as the process for industrially producing colorless polyetheresteramides with high degree of polymerization.
In view of the above, the present inventors have made an earnest study for the production of colorless polyetheresteramides with high degree of polymerization which are excellent in their light weight, low temperature performance, chemical resistance, oil resistance, sound proofness and moldability and, as the result, have accomplished this invention on the basis of the discovery that a colorless polyetheresteramide can be obtained by using one or more polyamide-forming compound selected from the group consisting of aminocarboxylic acids and lactams, a dicarboxylic acid and a polyoxyalkylene glycol as the starting materials and subjecting them to polycondensating reaction in the presence of 0.0001 to 0.00999% by weight, based on the total weight of the above-mentioned reaction mixture, of a catalyst containing a tetraalkyl titanate under high vacuum (lower than 5 mmHg) at a temperature between 200.degree.-300.degree. C.